Pretty much unless you reformat your Wii’s internal memory.
I post from my Samsung Instinct every now and again. I tend not to use it a whole lot because it don’t have spell check like it does for my texts
I post about 99% of my posts from my PSP. In fact, I’m using my PSP right now. The only bad thing about using a PSP is that you can’t watch videos, you can’t view pages that are too big, and you have a limit to characters in each post.